Cell Cycle, Mitosis, Meiosis

Chromosome

Chromosome

A thread-like structure containing DNA. We have 46 chromosomes in each cell.

Chromatin

Chromosomes are full of chromatin which is DNA wrapped around histone proteins.

Sister chromatid

The two halves of chromosomes.

Centromere

The center part of the chromosome that the spindle fibers connect to.

Cell cycle

The process of cells dividing, differentiating, or dying.

Interphase

The process where cells get ready to undergo mitosis.

G1 phase

The cell increases in size and prepares for duplicating its DNA.

S phase

The DNA replicates and there are now two sets of chromosomes.

G2 phase

The cell continues growing and preparing for replication.

Mitosis

Division of the chromosomes in a cell’s nucleus.

Centrioles

Spindle fibers are connected to the centrioles.

Spindle fibers

Spindle fibers attach to the centromeres of chromosomes during metaphase.

Prophase

The first step of mitosis; nuclear membrane breaks apart; chromatin condenses into chromosomes

Metaphase

Chromosomes line up in the middle of the cell called the metaphase plate; spindle fibers attach to centromeres.

Anaphase

The spindle fibers pull the chromatids apart and move to opposite sides of the cell.

Telophase

Two nuclei are formed; spindle fibers disappear; chromosomes uncoil and become chromatin again; nuclear membrane reappears.

Cytokinesis

The cytoplasm splits into the two cells.

Meiosis I

The first of two cell divisions in gametes.

Crossing over

Exchange of DNA between sister chromatids of homologous chromosomes forms recombinant DNA.

Meiosis II

The second cell division for gametes.

Homologous chromosomes

Chromosomes that have matching pairs.

Tetrad

A pair of homologous chromosomes.

Haploid

1 complete set of chromosomes

Diploid

2 complete sets of chromosomes

Body or somatic cell

Every cell except reproductive cells.

Gamete

Only gametes.

Chromosomal mutation - deletion

Loss of all or part of a chromosome.

Chromosomal mutation - duplication

Extra parts of a chromosome are produced.

Chromosomal mutation - inversion

Reverse in the direction of parts of chromosomes.

Chromosomal mutation - reciprocal translocation

Part of one chromosome breaks off and attaches to another.